Taking the example of optical power meters, it is well known that microprocessors are used in such apparatus for adapting the power meter readout to the light input-to-electric signal output of the photodetector. A memory integrated circuit in such apparatus is pre-programmed with the calibration information on detectors used with that apparatus. In practice, this limits the power meter to use with one detector or with a narrow range of functionally equivalent detectors.
For increased versatility in this respect, another approach has been to combine the programmable memory integrated circuit in one unit with the detector to which the calibration information with which that memory integrated circuit has been programmed pertains. This liberated the power meter for use with detectors of various characteristics, but, in turn, limited the photodetector to use with the memory integrated circuit combined therewith.
This left a need for increased versatility in the optical power meter field, especially now that the fiber optics networks have become widespread and require enormous optical power measurement procedures at an increasing number of job sites, quite in addition to the increasingly demanding optical power measurements in laboratories and otherwise in research, planning, development, and performance evaluation and verification.
Similar needs can be discerned with other than optical radiant sensors which have specific radiant energy-to-electric signal response characteristics, and even with light emitting diodes, lasers or other electrically energized radiant energy emitters having an output controllable by input energization according to specific radiant output-to-electrical energization characteristics.